A lingering technical question about the Sept. 11 terrorist attacks
still haunts some, and it has political implications: How did 200,000
tons of steel disintegrate and drop in 11 seconds? A thousand
architects and engineers want to know, and are calling on Congress to
order a new investigation into the destruction of the Twin Towers and
Building 7 at the World Trade Center.

"In order to bring down this kind of mass in such a short
period of time, the material must have been artificially, exploded
outwards," says Richard Gage, a San Francisco architect and founder of the nonprofit Architects & Engineers for 9/11 Truth.

Mr. Gage, who is a member of the American Institute of Architects,
managed to persuade more than 1,000 of his peers to sign a new petition
requesting a formal inquiry.

"The official Federal Emergency Management [Agency] and
National Institute of Standards and Technology reports provide
insufficient, contradictory and fraudulent accounts of the
circumstances of the towers' destruction. We are therefore calling for
a grand jury investigation of NIST officials," Mr. Gage adds.

The technical issues surrounding the collapse of the towers has prompted years of debate, rebuttal and ridicule.

He is particularly disturbed by Building 7, a 47-story
skyscraper, which was not hit by an aircraft, yet came down in "pure
free-fall acceleration." He also says that more than 100
first-responders reported explosions and flashes as the towers were
falling and cited evidence of "multi-ton steel sections ejected
laterally 600 ft. at 60 mph" and the "mid-air pulverization of 90,000
tons of concrete & metal decking."